axum-login is a Rust library providing user identification, authentication, and authorization as tower middleware for Axum web applications. It enables pluggable authentication backends through well-designed traits (AuthUser, AuthnBackend, AuthzBackend) and offers flexible route protection via both macro-based and builder-based middleware APIs. The library uses tower-sessions for secure session management and includes features like session fixation mitigation and constant-time password verification. Examples demonstrate usage with various backends including SQLite, OAuth2, and permission-based systems.